Feed mechanism for bending machine

ABSTRACT

A feed mechanism for advancing an elongated planar sheet through a bending machine comprising a clamping mechanism for engaging an edge of said sheet, advancing mechanism mounted on a carriage which also mounts said clamping mechanism for advancing said sheet through said bending machine in increments, a pair of rails attached to said carriage and extending through said bending machine, and brake shoes on said bending machine for selectively engaging said rails during a bending operation so as to cause the rails to absorb the pull produced by the bending machine on the workpiece and thereby prevent such pull from being transmitted to the advancing mechanism on the carriage.

United States Patent [191 Kopczynski [451 May 27, 1975 FEED MECHANISM FOR BENDING MACHINE [76] Inventor: John F. Kopczynski, i671 Sweeney [52] US. Cl. 72/307; 72/420; 72/422 [51] Int. Cl. B2ld 43/10 [58] Field of Search 72/420, 422, 307, 301,

72/305, DIG. 11

[56] References Cited UNITED STATES PATENTS 3/1974 Kopczynski 72/420 10/1974 Van Dijk 72/307 Primary Examiner-Milton S. Mehr Attorney, Agent, or Firm.loseph P. Gastel [57] ABSTRACT A feed mechanism for advancing an elongated planar sheet through a bending machine comprising a clamping mechanism for engaging an edge of said sheet. advancing mechanism mounted on a carriage which also mounts said clamping mechanism for advancing said sheet through said bending machine in increments, a pair of rails attached to said carriage and extending through said bending machine, and brake shoes on said bending machine for selectively engaging said rails during a bending operation so as to cause the rails to absorb'the pull produced by the bending machine on the workpiece and thereby prevent such pull from being transmitted to the advancing mechanism on the carriage.

5 Claims, 9 Drawing Figures PATENTEB am 2 7 1975 SHEET FEED MECHANISM FOR BENDING MACHINE The present invention relates to an improved feed mechanism for a bending machine.

By way of background, corrugations are formed in a metal plate by advancing the plate through a bending machine in increments by means of a suitable feed mechanism. One type of arrangement for effecting this result is shown in US. Pat. No. 3,798,956 issued to John F. Kopczynski. In this machine a clamping unit on an advancing carriage yields during the bending action so as to prevent a pulling force exerted on the sheet by the bending machine from being transmitted to the advancing mechanism. It has been found, however, that if the portion of the workpiece between the advancing mechanism and the bending machine is maintained in tension during the bending operation, a superior prod uct is obtained. However, if the clamping mechanism in a machine such as described in the above patent should be restricted against yielding, then the pulling force exerted on the workpiece would be transmitted to the advancing mechanism on the advancing carriage, and since such a pulling force would be exerted from 60 to 80 times per minute, the advancing mechanism could be damaged, as it is not built to stand this type of shock.

In the past pressure feet were utilized in conjunction with the bending machine for engaging the portions of the workpiece immediately adjacent the bending dies with a force sufficient to prevent the pulling force on the workpiece from being transmitted to an advancing carriage. However, in structure of this type, the workpiece could not be overbent, as required in making certain corrugations, to compensate for the spring-back of the material. In other words, because of the rigid manner in which the pressure blocks enaged the workpiece immediately adjacent the bending area, there was no allowance for the required springback. Furthermore in installations of this type, the portion of the workpiece between the feed carriage and the bending machine was not placed in tension during the bending operation, and therefore an improved product could not be obtained.

It is accordingly the object of the present invention to provide an improved advancing mechanism for incrementally feeding a sheet of material through a bending machine and for maintaining a tension on the sheet during the bending process without permitting the tension so produced from being transmitted to the advancing mechanism associated with the carriage.

The improved feed mechanism of the present invention for advancing an elongated member having a longitudinal axis through a bending machine comprises attachment means for attachment to said member, advancing means coupled to said attachment means for intermittently advancing said member through said bending machine in predetermined increments in the direction of said longitudinal axis, said advancing means being spaced from said bending machine along said longitudinal axis so that a portion of said member which is not engaged by said attachment means or said bending machine lines between said attachment means and said bending machine, and reinforcement means connecting said advancing means and said bending machine for absorbing the pulling force exerted on said elongated member by said bending machine during bending, thereby preventing said pulling force from being transmitted to said advancing means through said elongated member.

The various aspects of the present invention will be more fully understood when thefollowing portions of the specification are read in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic plan view of the improved feed mechanism of the present invention shown in relation to a bending machine;

FIG. 2 is a fragmentary perspective view of the workpiece which is formed by a bending machine operating in conjunction with the feed mechanism of the present invention;

FIG. 3 is a fragmentary schematic side elevational view showing the manner in which a workpiece is deformed by certain prior art machines;

FIG. 4 is a fragmentary schematic side elevational view showing the manner in which a workpiece is deformed by a bending machine acting in conjunction with the improved feed mechanism of the present invention;

FIG. 5 is a fragmentary view, partially in cross section, taken substantially along line 5-5 of FIG. 1 and showing various details of the advancing means for advancing a workpiece in increments through a bending machine; 1

FIG. 6 is a fragmentary cross sectional view taken substantially along line 6-6 of FIG. 5;

FIG. 7 is a fragmentary plan view taken substantially along line 7-7 of FIG. 6;

FIG. 8 is a fragmentary cross sectional view through the bending machine taken substantially along line 5-5 of FIG. 1 and showing the relationship between the braking mechanism and the strut which is connected to the advancing means; and

FIG. 9 is a fragmentary cross sectional view taken substantially along line 9-9 of FIG. 8.

The improved feed mechanism of the present invention is related to the feed mechanism disclosed in US. Pat. No. 3,798,956 issued to John F. Kopczynski on Mar. 26, 1974. In the patented feed mechanism there is disclosed an advancing mechanism for advancing a sheet through a bending machine in increments. In that mechanism the clamping means which engage the end of the sheet to advance it through the bending machine are mounted in a floating manner both vertically of the sheet and longitudinally of the sheet so as to permit the sheet to yield as required when it is acted on by the bending machine. In the feed mechanism of the present invention, however, the clamping means which pull the sheet through the bending machine do not yield and therefore the pull on the sheet during bending could be transmitted to the advancing mechanism if it were not for the strut arrangement which is utilized between the bending machine and the advancing mechanism to absorb this pull and thus prevent it from causing the advancing mechanism from being subjected to forces which might detrimentally affect it. However, notwithstanding that there is the above described basic difference between the feed mechanism of the patent and the feed mechanism disclosed here, it will be understood that there are certain areas of similarity, and insofar as such areas of similarity do exist, the above mentioned US. Pat. No. 3,798,956 is incorporated into this specification by reference.

Broadly, the improved feed mechanism 10 of the present invention is utilized in conjunction with a bending machine 11 through which a planar metal sheet 12 is pulled in increments to produce corrugations 13 therein. More specifically, the feed mechanism comprises a feed table 14 on which carriage 15 is mounted for movement toward and away from bending machine 11. A plurality of attaching or clamping feet 16 bear downwardly on the top of sheet 12 (FIG. so as to hold it against anvils 17 mounted on bases 18. Each foot 16 is actuated by a hydraulic piston and cylinder unit 19 connected to link 20 on which each foot 16 is mounted. Suitable cam mechanism associated with each piston and cylinder unit 19 produces the proper motion of leg 16 to effect the above described clamping action. As can be seen from FIGS. 1, 5, 6 and 7, all of the motor units 19 are mounted on a beam 21 attached by vertical plates 22 and 23 to upper plate 20 which forms a part of carriage 15. It can thus be seen that whenever sheet 12 is clamped by feet 16 and carriage is caused to move, it will pull sheet 12 through bending machine 11.

As noted briefly above, carriage 15 is caused to move to the left in FIG. 1 in increments, these increments being equal to the spacing between the centerlines of corrugations 13 in sheet 12. Broadly, the mechanism for advancing sheet 12 comprises a pair of spaced parallel upstanding side walls 22 extending upwardly from plate and located on opposite sides of the carriage, proximate the outer sides of the table 14. Side walls 22 are connected by plates 24 and 25 which extend therebetween. A piston and cylinder type of fluid motor 23 is pivotally mounted by pin 24 on each side wall 22 and it receives pressurized fluid from a suitable source through conduits 25 or 26 which are coupled thereto. A lever 27 has a boss 28 located centrally thereof which is mounted pivotally at 29 by a trunnion connection with member 30 which is secured at the outer end of motor piston rod 31. The left end of lever 27 (FIG. 5) is pivotally mounted on pin 32 at the lower end of leg 33 of plate 22, pin 32 extending through leg 33 and boss 34 on lever 27. An arm 35 (FIG. 5) has its left end pivotally mounted on pin 36 which is mounted on portion 37 of lever 27. The right end of member 35 mounts a pin 38 which is selectively received in scallops 39 of rail 40 on table 14. At this point it will be noted that there are two rails 40 (FIG. 1), one on each side of table 14 and there are two levers 27, one on each side of carriage 15, although only one is shown in the drawings for the sake of simplicity.

In operation, whenever piston rod 31 of motor 23 is extended, pin 38 at the end of link 35 will enter the scallop 39 above which it is located and as piston 31 continues to extend, link 27 will pivot about pin 32 in a clockwise direction so as to cause the toggle linkage formed by lever 27 and member 35 to straighten out, and this will cause carriage 15 to move to the left. It will be appreciated that carriage 15 will only move a distance to the left which is the difference in length between the centers of pins 32 and 38 when lever 27 and member 35 are in the position shown in FIG. 5 and when they are in a straightened position. It will be appreciated that while a specific type of advancing linkage has been shown relative to carriage 15, the advancing linkage shown in Kopczynski U.S. Pat. No. 3,798,956 may be used in the environment of the present invention and, insofar as this is possible, this subject matter is incorporated by reference herein.

At this point it is to be noted from FIGS. 5 and 6 that carriage 15 is mounted on a plurality of spaced rollers 42 mounted at one side of carriage 15 and these rollers travel on surface 43 forming a part of plate 44 which is mounted on leg 45 forming one side of table 14. As can be seen from FIG. 7, the opposite side of carriage 15 is mounted on spaced forked arms each mounting a pair of rollers 46 and 47, oriented as shown, which ride on surfaces 48 and 49, respectively, of rail 50. mounted on elongated plate 51 which in turn is supported on the top of leg 52 of table 14. Rollers 46 and 47, because of their orientation relative to rail 50, prevent carriage 15 from moving laterally across the table during its longitudinal motion.

In order to cause carriage 15 to remain square relative to table 14, that is, so that it will not cock during its travel, a pair of pinions 53 and 54 are keyed to opposite ends of shaft 55 and their teeth are in exact alignment with each other. Pinions 53 and 54 are in mesh with racks 56 and 57, respectively, which extend lengthwise of table 14 and are mounted on the undersides of elongated plates 58 and 59, respectively, secured to plates 60 and 61, respectively. Plates 58 and 60 are maintained in elevated position above plates 44 by plate 62, and plates 59 and 61 are maintained in elevated position above plate 51 by plate 63 (FIG. 6). In addition to performing the above noted function of causing the carriage to run true, without cocking, on table 14, the pinions 53 and 54 are used to cause carriage 15 to traverse from left to right in FIG. 1 after a bending operation has been completed and the completed plate has been removed from the machine. For this purpose, a motor and associated structure, not shown, is caused to drive shaft 55, as described in greater detail in the above mentioned U.S. Pat. No. 3,798,956, and such structure is incorporated here by reference.

At this point it is to be noted that in the machine of U.S. Pat. No. 3,798,956 the planar sheet 12 is deformed into corrugated sheet 12 in the manner shown in FIG. 3 whereby the material is deformed equally from opposite sides of the centerline A. In other words, points a and a will be used as reference points. Points b and c will move equally toward point a and assume positions b and c, respectively. Points d and e will move to positions d and 2, respectively. It will thus be seen that during deformation points equally spaced on opposite sides of center point a will have moved equal distances toward point a.

However, in accordance with the operation of the feed mechanism of the present invention, workpiece 12 shown in FIG. 4 is deformed into workpiece 12' because the clamping mechanism, as mounted on carriage 15, prevents equal distortions of the type described above relative to FIG. 3. In this respect, because workpiece 12 is held at the left against movement toward the right in FIG. 4, the reference line about which deformation occurs is line B. In this respect, pointfon the undeformed plate 12 will become point f on plate 12, but it will be seen that there has been no movement of pointfto the left. However, the next point g will move slightly to the left to become g, point It will move to h, and pointj will move toj. Point k will move to k and point I will move to point I. It can thus be seen that there is a movement of the material in the directions of the arrows pointing to the left at the top of FIG. 4.

Comparing the prior art deformation of FIG. 3 with the deformation shown in FIG. 4, it can be seen that at point j the material has been moved a distance 65 to the left. This type of action, which keeps the sheet taut during deformation, has a plurality of beneficial effects. More specifically, a stretching action is applied between the portion of the workpiece being deformed in the bending machine and the portion being held by the clamping feet 16 so that this stretching overcomes basic irregularities in the sheet stock before deformation, these irregularities being known as oil canning which means that the sheet is not perfectly planar. Furthermore, because of the maintaining of the sheet taut during deformation, there is extra work placed in each forming step which causes a superior product.

The above described action which causes the portion of the workpiece between the clamping mechanism and the punch press to be tensioned occurs 60 to 80 times per minute, the frequency of movement of the carriage. Each tensioning action produces approximately 500 pounds of tension on the workpiece. This force, at the rate of 60 to 80 times per minute could be transmitted to the indexing mechanism on the carriage if there were no structure to prevent this, and since the indexing mechanism is relatively fragile, after absorbing a certain number of shocks, there could be a malfunction. The structure of the present invention prevents the transmission of shock to the indexing mechanism and therefore not only insures that the workpiece will be held under tension without yielding to provide a superior product, but also that such shock will not be transferred to the indexing mechanism on the carriage. To achieve this, a pair of struts or reinforcement means 67 and 68 in the shape of inverted T-shaped rail members are provided. Each member terminates in an end portion 69 and 70, respectively, which is of substantially rectangular solid configuration. Pins 71 and 72 extend through portions 69 and 70, respectively, to attach them to plate 21 on carriage 15.

As can be seen from FIGS. 8 and 9, the lower bending die 74 is mounted on base member 75 of the bending machine, and upper die 76 is mounted on ram 77 of the bending machine. A brake mechanism is also mounted on each side of the bending machine for selectively engaging struts 67 and 68. However, only the brake mechanism associated with strut 67 will be described, it being understood that an identical brake mechanism is associated with strut 68. A block 79 is secured to one side of ram 77 by means of screws 80. A plurality of bolts 81 each have neck portions 82 which are slidably received in bores 83 of block 79. The lower ends 84 of bolts 81 are threadably received in shoes 85 and 86 which are mirror images of each other. A spring 87 has its upper portion received in cylindrical recess 88 in block 79 and its lower portion received in cylindrical recess 89 in shoe 85. A spring 90 which encircles bolt 81 has its upper portion received in cylindrical recess 91 in block 79 and its lower portion received in cylindrical recess 92 in block 86. Block 79 is mounted on the opposite side of ram 77 from block 79 and it constitutes a mirror image counterpart of block 79, and accordingly, primed numerals will be applied thereto with the understanding that such primed numerals correspond to the analogous elements of structure desig' nated by unprimed numerals relative to block 79. Block 79A (FIG. 1) is identical to block 79, and block 79B is identical to block 79.

Whenever ram 77 is in its lowermost descended position, the undersurfaces 94 and 95 of shoes and 86, respectively, will engage surfaces 96 and 97, respectively, of the horizontal portion 98 of T-bar 67 to provide a braking action thereon, as T-bar 67 rests on block 102 mounted on machine base 75. Another block 102 is associated with T-bar 68. Lugs 104 and 106 extending upwardly at the four corners of each block 102 prevent shoes 85 and 86 from moving longitudinally with rails 67 and 68 during the braking action. In addition, lugs 104 and 106 guide shoes 85 and 86 vertically during upward and downward movement of ram 77. It is to be especially noted that the braking action on bar 67 is impressed through the four springs associated with the four bolts 81 and 81' so as to provide a resilient braking action. An identical action is applied to T-bar 68 through blocks 79A and 79B and the brake shoes analogous to shoes 85 and 86 and a block 102 as sociated therewith. The braking action is applied to T- bars 67 and 68 shortly before the dies 76 and 74 act on the workpiece to deform it so that the force tending to pull the workpiece toward the bending machine is resisted by the compression of the T-bar struts 67 and 68 on opposite sides of the feed table. Thus, the pulling force on the workpiece is absorbed by struts 67, which are attached to beam 21, and by the clamping mechanism which is also mounted on beam 21. Because the forces are absorbed in this manner, they are not transmitted to the remainder of the carriage 15 or to the above described indexing mechanism mounted thereon. In addition, the foregoing mode of connection permits the portion of the workpiece between the carriage and the bending machine to be tensioned to provide a superior product.

Whenever ram 77 ascends so that dies 74 and 76 are separated, the upper blocks 79, 79, 79A and 793 will move upwardly with ram 77, thus allowing springs -90 and the analogous springs (not shown) associated with blocks 79A and 79B to expand until a point is reached wherein heads and 100' of all of the bolts such as 82 and 82', respectively, rest on the top surfaces of blocks 79 and 79', respectively, and thus after this contact is obtained, the lower blocks or brake shoes 85 and 86 will be moved upwardly out of engagement with struts 67 and 68 so as to permit them to move unrestrictedly to the left in FIG. 5 as the carriage indexes. However, after the ram 77 again descends, after the workpiece has been properly indexed, the above described braking action will again be obtained immediately prior to the time that the dies engage the workpiece to produce another corrugation 13 therein. It is to be again emphasized, that the same braking action produced on T-bar 67 by structure described in detail above is also produced on T-bar 68 by analogous structure so that both struts 67 and 68 absorb the pulling force on the portion of the workpiece between the advancing carriage and the bending machine.

It can thus be seen that the improved feed mechanism of the present invention is manifestly capable of achieving the above enumerated objects, and while preferred embodiments of the present invention have been disclosed, it will be appreciated that it is not limited thereto but may be otherwise embodied within the scope of the following claims.

What is claimed is:

1. A feed mechanism for advancing an elongated member having a longitudinal axis through a bending machine comprising attachment means for attachment to said member, advancing means coupled to said attachment means for intermittently advancing said member through said bending machine in predetermined increments in the direction of said longitudinal axis, said advancing means being spaced from said bending machine along said longitudinal axis so that a portion of said member which is not engaged by said attachment means or said bending machine lies between said attachment means and said bending machine, and reinforcement means connecting said advancing means and said bending machine for absorbing the pulling force exerted on said elongated member by said bending machine during bending thereby preventing such pulling force from being transmitted to said advancing means through said elongated member.

2. A feed mechanism as set forth in claim 1 wherein said reinforcement means comprises elongated means including a first portion coupled to said advancing means and a second portion spaced from said first portion, and means on said bending machine for engaging said second portion during bending of said elongated member to cause said pulling force to be absorbed by said elongated means.

3. A feed mechanism as set forth in claim 2 wherein said advancing means comprises a table, a carriage, means on said table for mounting said carriage, said attachment means and said advancing means being mounted on said carriage, and wherein said elongated means comprises strut means.

4. A feed mechanism as set forth in claim 3 wherein said means on said bending machine for engaging said second portion comprises brake means.

5. A feed mechanism as set forth in claim 4 wherein said strut means comprises first and second rails which are spaced laterally from each other. 

1. A feed mechanism for advancing an elongated member having a longitudinal axis through a bending machine comprising attachment means for attachment to said member, advancing means coupled to said attachment means for intermittently advancing said member through said bending machine in predetermined increments in the direction of said longitudinal axis, said advancing means being spaced from said bending machine along said longitudinal axis so that a portion of said member which is not engaged by said attachment means or said bending machine lies between said attachment means and said bending machine, and reinforcement means connecting said advancing means and said bending machine for absorbing the pulling force exerted on said elongated member by said bending machine during bending thereby preventing such pulling force from being transmitted to said advancing means through said elongated member.
 2. A feed mechanism as set forth in claim 1 wherein said reinforcement means comprises elongated means including a first portion coupled to said advancing means and a second portion spaced from said first portion, and means on said bending machine for engaging said second portion during bending of said elongated member to cause said pulling force to be absorbed by said elongated means.
 3. A feed mechanism as set forth in claim 2 wherein said advancing means comprises a table, a carriage, means on said table for mounting said carriage, said attachment means and said advancing means being mounted on said carriage, and wherein said elongated means comprises strut means.
 4. A feed mechanism as set forth in claim 3 wherein said means on said bending machine for engaging said second portion comprises brake means.
 5. A feed mechanism as set forth in claim 4 wherein said strut means comprises first and second rails which are spaced laterally from each other. 